1. Field
An aspect of the present invention relates to a printed circuit board having a semiconductor package and a board bonded by bonding portions.
2. Description of the Related Art
Among printed circuit boards for use in portable computers, there are some printed circuit boards mounted with semiconductor packages called Ball Grid Arrays (BGAs). In the BGA, solder balls are arrayed like a grid in a lower face of a semiconductor package, and each solder ball is connected to an electrode on a board. In order to monitor the mounting condition of the solder balls, the mounting condition is determined in some printed circuit boards using electrodes located in the four outermost circumferential corners of a region where the solder balls are mounted on the board. That is, a given test signal is supplied from a signal circuit to an electrode located in one of the four outermost circumferential corners, and the test signal is received from another electrode located in another of the four outermost circumferential corners through a pattern connecting the electrodes located in the four outermost circumferential corners. Based on the received test signal, a determination circuit determines whether soldering is poor or not in the electrodes located in the four outermost circumferential corners (see JP-A-2006-278946, for instance).
In some kind of BGA board, a semiconductor package is connected to the board through a plurality of solder balls, but another structure for fixing the semiconductor package to the board is also used in addition to the solder balls in order to ensure the reliability of the connection. For example, corner portions of the semiconductor package may be fixed to the board through bonding portions made of resin.
Stress is usually imposed on the BGA from the outside. Therefore, the bonding portions applied to the outer circumference of the BGA will be separated before the BGA is separated. When separation of the bonding portions is found out in the case where a semiconductor package is bonded by use of the bonding portions, separation of solder balls connecting the BGA to the board can be therefore known beforehand in an earlier stage.